Most modern day automobile vehicles include in their heating systems devices for directing heated air over the vehicle's windshield in order to defrost and/or defog the same. Since these heating systems rely on engine generated heat for heating the air which is to be directed over the windshield, the systems take a few minutes before they are fully operable after a cold start of the vehicle. Since many drivers are impatient, they often will start movement of their vehicle before the windshield is fully defrosted or defogged thereby creating a hazardous condition.
The prior art has also taught some quick defrost and/or defog systems but, in general, these structures are relatively expensive. For example, some of the vehicles manufactured by the Ford Motor Company in the 1974 through 1976 model years were equipped with a quick defrost windshield in which the interlayer used for laminating the windshield contained a conductive coating thereon. The windshield was heated, in its entirety by applying an electrical current to the interlayer's conductive coating. This type of quick defrost system was expensive to manufacture because the conductive coating was formed from gold.
It is an object of this invention to provide a relatively low cost windshield heating device which provides added heat for windshield defrosting and/or defogging at times of a vehicle cold start. It is a further object of this invention to provide such a windshield heating device which is relatively economical to build and which is efficient in operation.